using ComputerShopContracts.BindingModels;
using ComputerShopContracts.ViewModels;
using ComputerShopDataModels.Models;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace ComputerShopDatabaseImplement.Models
{
	public class Assembly : IAssemblyModel
	{
		public int Id { get; private set; }

        [Required]
        public string AssemblyName { get; private set; } = string.Empty;

        [Required]
        public double Cost { get; private set; }

        [Required]
		public int UserId { get; private set; }

		[ForeignKey("ComponentId")]
		public virtual List<AssemblyComponent> Components { get; set; } = new();

		private Dictionary<int, (IComponentModel, int)>? _assemblyComponents;

		[NotMapped]
		public Dictionary<int, (IComponentModel, int)> AssemblyComponents
		{
			get
			{
				if (_assemblyComponents == null)
				{
					_assemblyComponents = Components.ToDictionary(
						AsmComp => AsmComp.ComponentId, 
						AsmComp => (AsmComp.Component as IComponentModel, AsmComp.Count)
					);
				}

				return _assemblyComponents;
			}
		}

		public static Assembly Create(ComputerShopDatabase Context, AssemblyBindingModel Model)
		{
			return new()
			{
				Id = Model.Id,
                AssemblyName = Model.AssemblyName,
                Cost = Model.Cost,
                UserId = Model.UserId,	
				Components = Model.AssemblyComponents.Select(x => new AssemblyComponent
				{
					Component = Context.Components.First(y => y.Id == x.Key),
					Count = x.Value.Item2
				}).ToList(),
			};
		}

        public void Update(AssemblyBindingModel Model)
        {
            if (!string.IsNullOrEmpty(Model.AssemblyName))
            {
                AssemblyName = Model.AssemblyName;
            }

            Cost = Model.Cost;
        }

        public void UpdateComponents(ComputerShopDatabase Context, AssemblyBindingModel Model)
        {
            var AssemblyComponents = Context.AssemblyComponents.Where(x => x.AssemblyId == Model.Id).ToList();
            if (AssemblyComponents != null && AssemblyComponents.Count > 0)
            {
                Context.AssemblyComponents
                    .RemoveRange(AssemblyComponents
                    .Where(x => !Model.AssemblyComponents.ContainsKey(x.ComponentId)));
                Context.SaveChanges();

                foreach (var ComponentToUpdate in AssemblyComponents)
                {
                    ComponentToUpdate.Count = Model.AssemblyComponents[ComponentToUpdate.ComponentId].Item2;
                    Model.AssemblyComponents.Remove(ComponentToUpdate.ComponentId);
                }

                Context.SaveChanges();
            }

            var CurrentAssembly = Context.Assemblies.First(x => x.Id == Id);
            foreach (var AssemblyComponent in Model.AssemblyComponents)
            {
                Context.AssemblyComponents.Add(new AssemblyComponent
                {
                    Assembly = CurrentAssembly,
                    Component = Context.Components.First(x => x.Id == AssemblyComponent.Key),
                    Count = AssemblyComponent.Value.Item2
                });

                Context.SaveChanges();
            }

            _assemblyComponents = null;
        }

        public AssemblyViewModel ViewModel => new()
        {
            Id = Id,
            AssemblyName = AssemblyName,
            Cost = Cost,
            UserId = UserId,
            AssemblyComponents = AssemblyComponents,
        };

    }
}